This application claims the benefit of a Japanese Patent Application No.2000-301461 filed Sep. 29, 2000, in the Japanese Patent Office, the disclosure of which is hereby incorporated by reference.
1. Field of the Invention
The present invention generally relates to rotation control methods for recording media and storage apparatuses, and more particularly to a rotation control method for controlling rotation of a recording medium such as an optical disk, and to a storage apparatus which employs such a rotation control method.
Recording media such as optical disks employ a zone constant angular velocity (ZCAV) system or a zone constant linear velocity (ZCLV) system. When the ZCAV system is employed, it is possible to obtain a high random access performance with respect to the recording medium, but a recording and/or reproducing clock frequency becomes low. For example, a data transfer rate at an inner periphery of the optical disk becomes slow. On the other hand, when the ZCLV system is employed, it is possible to obtain a high data transfer rate, but the random access performance with respect to the recording medium becomes poor because the rotational speed of the recording medium such as the optical disk changes upon access thereto.
2. Description of the Related Art
Recently, due to the popular use of the Internet, there are increased opportunities for users to download data, such as music and video data, via a communication line or the like, and to record the downloaded data in recording media. In such cases, magnetic disks of a hard disk drive (HDD), and removable optical disks such as a digital versatile disk random access memory (DVD-RAM) are used as the recording media.
In the case of the video data, the size of one file is relatively large. In addition, the video data is a continuous data, and it is necessary to continuously and stably maintain the data transfer rate over a predetermined value during recording to or reproduction from the optical disk, in order not to generate an image distortion such as frame dropout.
On the other hand, in personal computers or the like, a disk management area is usually provided in a portion of the optical disk for the purposes of managing programs and files. Accordingly, it becomes necessary to access the disk management area every time an access is made to the program or file. For this reason, in a case where the size of each file is relatively small, the access to the file and the access to the disk management area are repeated, to thereby generate a random access to the optical disk.
Therefore, the required data transfer rate and the required random access performance differ depending on the state of use of the recording medium, such as the kind of data processed, the file size and the usage of the recording medium.
Conventionally, there was a problem in that the data transfer rate and the random access performance cannot be set appropriately depending on the state of use of the recording medium, such as the kind of data processed, the file size and the usage of the recording medium.
Accordingly, it is a general object of the present invention to provide a novel and useful rotation control method and storage apparatus, in which the problems described above are eliminated.
Another and more specific object of the present invention is to provide a rotation control method and a storage apparatus which can set a data transfer rate and a random access performance to optimum values depending on a state of use of a recording medium.
Still another object of the present invention is to provide a rotation control method for controlling a recording medium which is divided into a plurality of zones in a radial direction thereof and employing a ZCAV system, where the rotation control method comprises the step of (a) switching a mode between a normal mode in which the recording medium is controlled to rotate at a first rotational speed, and a high-speed mode in which the recording medium is controlled to rotated at a plurality of second rotational speeds respectively corresponding to a plurality of areas to which the recording medium is divided in the radial direction thereof. According to the rotation control method of the present invention, it is possible to set a data transfer rate and a random access performance to optimum values depending on a state of use of the recording medium.
A further object of the present invention is to provide a storage apparatus having a function of controlling rotation of a recording medium which is divided into a plurality of zones in a radial direction thereof and employing a ZCAV system, comprising a setting part setting a mode to one of a normal mode in which the recording medium is controlled to rotate at a first rotational speed, and a high-speed mode in which the recording medium is controlled to rotated at a plurality of second rotational speeds respectively corresponding to a plurality of areas to which the recording medium is divided in the radial direction thereof. According to the storage apparatus of the present invention, it is possible to set a data transfer rate and a random access performance to optimum values depending on a state of use of the recording medium.
Another object of the present invention is to provide a storage apparatus having a function of controlling rotation of a recording medium which is divided into a plurality of zones in a radial direction thereof and employing a ZCAV system, comprising a controller switching and controlling a rotational speed of the recording medium in a plurality of stages when making an access from an arbitrary one of a plurality of areas to which the recording medium is divided in the radial direction to an area located on an inner peripheral side or an outer peripheral side of the recording medium relative to the arbitrary area, so that a data transfer rate becomes 3700 Kbyte/s or greater when making the access to the area located on the inner peripheral side of the recording medium relative to the arbitrary area. According to the storage apparatus of the present invention, it is possible to set a data transfer rate and a random access performance to optimum values depending on a state of use of the recording medium.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.